In general, many drugs are stored in vials (drug storage containers) which are each sealed with a rubber stopper (see, for example, Patent Document 1).
In the case of taking a drug, for example, a powdery drug out of such a vial, an injection needle is attached to a distal end of a syringe in which a liquid for dissolution is stored, and the rubber stopper of the vial is punctured by the injection needle, to inject the liquid for dissolution into the vial. As a result, a dissolution liquid with the drug dissolved therein (hereinafter referred to as “a drug solution”) is obtained. In the case of such a vial, however, the liquid for dissolution flowing out from the injection needle would vigorously drip down directly to the drug, resulting in foaming in the drug solution (generation of bubbles in the drug solution). Thus, at the time of sucking the drug solution from the vial by use of the syringe or the like, there may be problems that it is impossible to achieve accurate metering and that unevenness of concentration of the drug solution is generated.
Patent Document 1: Japanese Patent Laid-open No. 2006-55452